Zenner pleaded guilty last September to one count of obtaining a controlled substance by fraud.

In his plea agreement, Zenner admitted that he siphoned Dilaudid from IV bags at a St. Cloud hospital from November 2010 to March 2011. Prosecutors say he sometimes injected the bags with saline solution to replace the missing Dilaudid. The government alleges about 25 hospital patients were infected with bacteria as a result.